Tape cartridge with mount plate

ABSTRACT

A tape cartridge having a solid metal mount plate including a plurality of surfaces thereon simultaneously machined to the same plane. Tape reels and tape guides are affixed to the mount plate, thereby ensuring precise alignment to each other. A portion of at least one of the surfaces is exposed to the outside of the tape cartridge by recesses in the tape cartridge cover. Upon seating the tape cartridge in a tape drive, guides are inserted into the recesses, thereby ensuring precise alignment of the tape to a tape head in the tape drive.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a tape cartridge having a mount plate. Moreparticularly, the invention is a tape cartridge having a mount plateincluding a plurality of surfaces thereon machined to the same plane, aportion of which is exposed to the outside of the tape cartridge byrecesses in the tape cartridge cover, to permit precise alignment of thetape reels, tape guides, and a tape head in a tape drive.

2. Description of the Related Art

Tape is a know medium for the storage of audio, video, and computerinformation. The information is typically written to and read from thetape magnetically and/or optically. Such tapes are available spooled onindividual reels and in single or dual reel tape cassettes/cartridges.The tape in a single reel tape cartridge must be mechanically threadedthrough the tape path and spooled onto a take-up reel after insertioninto a tape device/drive. The tape path for any type of tape cartridgeand tape drive includes a tape head in close proximity to the tape andhaving one or more transducer elements for writing to and/or readingfrom the tape. The tape is driven past the tape head by a capstan, or bydirect drive of the tape reels. As used herein, the terms "cassette" and"cartridge", and the terms "device" and "drive" are interchangeable.

For reliable operation of a tape drive, a tape cartridge and the tapetherein must be capable of being accurately aligned to one or more tapeheads in the tape drive. Known tape cartridges have shells (i.e. outermaterials) manufactured from plastic or other materials which deformeasily from mechanical and/or thermal stress. Such stresses may occurduring the storage, manual handling, and automated handling of the tapecartridges, including the mounting and demounting of the tape cartridgesin a tape drive. In addition, similar materials are used for theinternal parts of known tape cartridges. Such materials make accuratealignment of the tape and tape heads difficult, and subject toalteration during aging and handling. Finally, known tape cartridgesinclude various moving parts. For example, tape reels are known to bemovable laterally (i.e. along the axis of rotation within a tapecartridge to permit them to be moved into and out of engagement with atape reel brake. Such lateral movement further degrades the ability toaccurately align the tape and tape heads. Thus, a heretoforeunrecognized problem is the creation of a tape cartridge in which thetape therein can be accurately and repeatedly aligned with tape heads ina tape drive.

Another problem associated with tape drives and tape cartridges is thatof pneumatic tape guiding. Pneumatic tape guides using air bearings tosupport the tape are known in various tape drives. Such tape guides aredesirable for high performance tape paths. However, such tape guides usemetal stock to create a precisely shaped and smoothly polished tapepath. Such metal stock is expensive and must be machined or die-castinto the desired shape and contour. In addition, dual reel tapecartridges usually require tape guides in the cartridge. The use of suchmetal stock and complex machining increases the cost of tape cartridges,traditionally a low cost item used in large quantity. Gas bearing tapeguides having a metal foil affixed to a plenum in a tape drive have beenattempted, but have been unsuccessful because of the materials andmanufacturing techniques employed. Thus, a heretofore unrecognizedproblem is the creation of a dual reel tape cartridge which includespneumatic tape guiding for a high performance tape path while minimizingcost.

Another problem associated with tape drives and tape cartridges is thatof tape edge guiding. Tape edge guiding is typically provided bylocating compliant guides adjacent the bearing surface, which isslightly narrower than the tape. The tape thickness is minimized topermit the maximum amount of tape in a tape cartridge. As the tapethickness is reduced, the tape becomes more susceptible to tapevibrations resulting from the tape folding over the edge of the narrowerbearing surface. Tape vibrations are reduced by providing full bearingsupport for the tape across its width (i.e. the tape is narrower thanthe supporting bearing surface). Compliant members are again locatedadjacent the bearing surface to maintain the tape thereover. When thetape temporarily wanders off of the bearing surface, and before the tapeis guided back thereover, the edge of the tape is unsupported by thebearing surface. Such lack of support again renders the edge of verythin tapes susceptible to vibrations which can propagate along the tapeand eventually disrupt the head-tape interface. Compliant guides fittedwithin recesses in thick bearing surfaces in a tape drive to provideadditional tape edge support are known, but are not practical for use ina tape cartridge. Thus, a heretofore unrecognized problem is theelimination of tape vibration resulting from a lack of tape edge supportduring edge guiding.

Another problem associated with tape drives and tape cartridges is thatof contamination. Dust, wear particles and other contaminants can causesignal dropout and the abrasion of moving parts and thus degradeperformance of a tape drive and/or tape cartridge. The cleaning of tapedrives and tape cartridges using various mechanical and chemicaltechniques is known. However, the high performance tape drives of thefuture will not be able to tolerate the levels of contamination found incurrent tape drives, before or after such cleaning.

Tape cartridges are particularly susceptible to contamination whenremoved from a tape drive. Dust, wear particles and other contaminantsthat enter the interior of a tape cartridge migrate throughout thecartridge and can be transferred to a tape drive when the tape cartridgeis inserted therein. Some known tape cartridges include a tape accessdoor to reduce such contamination. The access door is opened when thetape cartridge is inserted into a tape drive to permit mating of thetape head and the tape. The access door is closed when the tapecartridge is removed from the tape drive.

Unfortunately, tape cartridges are susceptible to contamination throughother openings therein. One such opening permits access to a tape reelhub for proper seating of the tape cartridge in a tape drive and/or formating a motor driven clutch or gear to the hub for rotatably drivingthe hub. The clutch enters the tape cartridge opening and moves the hublaterally within the tape cartridge (i.e. depresses the hub away fromthe opening) to driveably mate with the hub. As previously mentioned,such movement of the hub degrades the ability to accurately align thetape and tape heads. Thus, a heretofore unrecognized problem is thecreation of a tape cartridge which achieves the high performancedemanded of future tape drives, including the aforementioned tape pathcharacteristics, yet minimizes tape cartridge contamination through hubaccess openings.

Another problem associated with dual reel tape cartridges is that oftape tension. In such tape cartridges the tape is always threadedbetween the tape reels. The precise control of tape tension when a tapecartridge is mounted in a tape drive is well known. Such controlincludes the sensing and mechanical adjustment of tape tension by thetape drive. When a dual reel tape cartridge is removed from the tapedrive, however, such control is no longer possible.

The tape tension varies as the tape moves therewithin during handling ofthe tape cartridge outside of the tape drive. When a dual reel tapecartridge is inserted into a tape drive the tape head is mated with thetape to press inwardly thereagainst. When the tape cartridge is removedfrom the tape drive, the absence of the tape head results in reducedtape tension between the tape reels (i.e. leaves slack in the tape). Theslack can migrate through the tape path during handling of the tapecartridge outside of the tape drive, causing the tape to unravel fromthe reels and become susceptible to damage. In addition, if the tapetension increases during handling outside of the tape drive (i.e. ispulled taut straight between the tape reels or tape guides of the tapecartridge), subsequent insertion of the tape cartridge into a tape drivemay result in stretching or other deformation degrades performance ofthe tape drive and/or tape cartridge. Thus, a heretofore unrecognizedproblem is the creation of a tape cartridge which maintains constanttape tension during handling of the tape cartridge outside of a tapedrive.

SUMMARY OF THE INVENTION

In view of the foregoing, it is the principal object of this inventionto improve tape cartridges.

Another object of this invention is a tape cartridge in which the tapetherein may be precisely aligned to a tape head in a tape drive.

These and other objects of this invention are accomplished by a tapecartridge having a solid metal mount plate including a plurality ofsurfaces thereon simultaneously machined to the same plane. Tape reelsand tape guides are affixed to the mount plate, thereby ensuring precisealignment to each other. A portion of at least one of the surfaces isexposed to the outside of the tape cartridge by recesses in the tapecartridge cover. Upon seating the tape cartridge in a tape drive, guidesare inserted into the recesses, thereby ensuring precise alignment ofthe tape to a tape head in the tape drive.

The foregoing and other objects, features, and advantages of theinvention will be apparent from the following more particulardescription of the preferred embodiment of the invention, as illustratedin the accompanying drawing.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is an isometric view of the tape cartridge according to theinvention

FIG. 2 is an isometric view of the tape cartridge with the pivotingaccess door open.

FIG. 3 is an isometric view of the tape cartridge from an alternateperspective.

FIG. 4 is an isometric view of the tape cartridge with the pivotingaccess door open from the alternate perspective.

FIG. 5 is an exploded, isometric view of the tape cartridge from thealternate perspective, with the pivoting access door open.

FIG. 6 is a top view of the tape cartridge with the cover and pivotingaccess door removed, and a tape head or pseudo-tape head inserted intothe tape path.

FIG. 7 is an isometric view of the tape cartridge mount and disengagedclutch faces which mate with the tape cartridge according to theinvention.

FIG. 8 is an isometric view of the tape cartridge mount and disengagedclutch faces from an alternate perspective.

FIG. 9 is an isometric view of the tape cartridge mount with the tapecartridge inserted therein and the clutch faces disengaged.

FIG. 10 is an isometric view of the tape cartridge mount with the tapecartridge inserted therein, and the clutch faces engaged, from thealternate perspective.

FIG. 11 is an isometric view of the tape cartridge mount with the tapecartridge inserted therein, and the clutch faces engaged, from yetanother perspective.

FIG. 12 is an isometric view of the pneumatic tape guide assembly of thetape cartridge.

FIG. 13 is an exploded, isometric view of the pneumatic tape guideassembly.

FIG. 14 is an exploded, isometric view of a toothed hub tape reel of thetape cartridge according to the invention.

FIG. 15 is an isometric view of a portion of the tape cartridgesectioned vertically at line AA, except for the hub axles.

FIG. 16 is a front view of a portion of the sectioned tape cartridge.

FIG. 17 is a top view of the pivoting access door with the upper flangeremoved.

FIG. 18 is an exploded, isometric view of the tape cartridge with anon-pneumatic tape guide assembly.

FIG. 19 is an isometric view of the tape cartridge with a sliding accessdoor.

FIG. 20 is an isometric view of the tape cartridge with a sliding accessdoor from an alternate perspective.

FIG. 21 is an isometric view of the tape cartridge with a sliding accessdoor open.

FIG. 22 is an isometric view of the tape cartridge with a sliding accessdoor open from an alternate perspective.

FIG. 23 is an exploded, isometric view of the tape cartridge with asliding access door open.

FIG. 24 is a top view of the sliding access door with the upper flangeremoved.

FIG. 25 is an exploded, isometric view of an alternate tape reel.

FIG. 26 is an isometric view of a portion of the tape cartridge with analternate tape reel and sectioned vertically at line AA, except for thehub axles.

FIG. 27 is a front view of a portion of the sectioned tape cartridgewith an alternate tape reel.

FIG. 28 is an exploded, isometric view of another alternate tape reel.

FIG. 29 is an isometric view of a portion of the tape cartridge withanother alternate tape reel and sectioned vertically at line AA, exceptfor the hub axles.

FIG. 30 is a front view of a portion of the sectioned tape cartridgewith another alternate tape reel.

DESCRIPTION OF THE PREFERRED EMBODIMENT

Referring now more particularly to the drawing, like numerals denotelike features and structural elements in the various figures. Theinvention will be described as embodied in a dual reel, tape cartridge.

Referring to FIG. 1, a tape cartridge 10 includes a box-like housingformed by a mount plate 12 and a cover 14. Cover 14 is secured to mountplate 12 by screws inserted through a set of holes 15-19. Cover 14 alsoincludes two holes 20 and 21 exposing portion of two tape reels. Asshown in FIG. 1, the tape reels are toothed hub tape reels. Cover 14includes two wall recesses represented by arrows 30 and 31. Wallrecesses 30 and 31 expose two mount portions 32 and 33, respectively, ofthe inner surface of mount plate 12. A pivoting access door 26 is hingedbetween mount plate 12 and cover 14 and is shown in the closed position.

Referring to FIG. 2, tape cartridge 10 is shown with access door 26pivoted to the open position, thereby exposing the inside of tapecartridge 10 through a head opening represented by arrow 25. The tape isnot shown in FIG. 2 to permit viewing of a portion of the tape guidingpath, as will be described. When access door 26 is pivoted to the openposition, one or more tape heads (not shown) may be brought into contactwith the tape to permit read and/or write access to data on the tape, aswill be described further herein.

Referring to FIGS. 3-4, tape cartridge 10 is shown from an alternateperspective. The position of access door 26 in FIG. 4 reveals two doorflanges 27 and 28 and a pseudo-head 29. When access door 26 is pivotedto the closed position, the tape is straddled by (i.e. travels in a pathbetween) upper flange 27 and lower flange 28. Pseudo-head 29 protrudesinward between flanges 27 and 28. When access door 26 is pivoted to theclosed position, pseudo-head 29 takes the place of the tape head in thetape path.

Referring to FIG. 5, tape cartridge 10 is shown exploded to expose theinside thereof. For convenience, no tape is shown. A set of screws 35-30are inserted through holes 15-19 and thread into a set of holes 45-49 inmount plate 12 to secure cover 14 to mount plate 12. A pin 62 securesmount plate 12 at a hole 63 to cover 14 at a hole 64. Pin 62 is insertedthrough hole 68 to permit pivoting of access door 26. A spring 69 biasesaccess door 26 toward its closed position.

Mount plate 12 includes various inner surfaces. A set of inner mountsurfaces 51-53 are in the same mount plane. Because mount surfaces 51-53are in the same plane, various tape cartridge components can beprecisely positioned relative to a tape cartridge mount (not shown) in atape drive and to each other, as will be described. An inner surface 50is recessed into the mount plane to permit the unobstructed rotation oftwo tape reels 200 and 300.

Several components of tape cartridge 10 or a tape cartridge mount aremounted to or interface with mount surface 51. A pneumatic tape guideassembly 100 is secured to mount surface 51. Two pins 55-56 locateassembly 100 to two holes 65-66, respectively. A hole 61 mates with thetape cartridge mount (not shown) for the passage of a gas from the tapedrive including the tape cartridge mount into the pneumatic tape guideassembly 100. A set of circular recesses 41 and 42 (collectivelyidentified for convenience) into the mount surface 51 allow gas to bleedfrom the edge of the tape, as it moves inside tape cartridge 10. Mountsurface 51 also includes mount positions 32-33, and holes 23-24, 45-48,59 and 63.

Two axles 72 and 73 are secured to mount surfaces 52 and 53,respectively. The hubs of two toothed hub tape reels 200 and 300 arerotatably mounted upon hub axles 72 and 73, respectively. Axles 72 and73 extend through two hub holes 202 and 203, respectively. Tape reels200 and 300 will be described further herein.

The pneumatic tape guide assembly 100 includes two nearly D-shaped tapeguiding bearings 105 and 125. The gas bearings include two plenums (oneplenum for each bearing) 110 and 130. Two thin bearing foils 160 and 180are mounted to plenums 110 and 130, respectively, as will be describedfurther herein. Plenums 110 and 130 include two holes 111 and 131,respectively, for mounting upon pins 55 and 56, respectively. Two screws112 and 132 secure plenums 110 and 130, through two holes 113 and 133,to holes 23 and 24 of mount plate 12 respectively. Two screws 116 and136 secure two compliant members 120 and 140, through two holes 117 and137, to plenums 110 and 130 respectively. Assembly 100 will be describedfurther herein.

Referring to FIG. 6, tape cartridge 10 is shown with cover 14 and,except as described hereafter with respect to pseudo-head 29, pivotingaccess door 26 removed. A tape 1 (dotted line) is shown wound on tapereels 200 and 300. Tape 1 may be wound from tape reel 300 to tape reel200, or vice-versa. For the former, tape 1 exits from tape reel 300 atregion 2, extends around bearing 125, through a head region 3, aroundbearing 105, forms a squeeze bearing 4 with tape still wound upon tapereel 300, and is spooled on to tape reel 200 at region 5. The tape pathis reversed when tape 1 is wound from tape reel 200 to tape reel 300.The tape is wound by the action of a motor (not shown) in the tape drivewhich drives a toothed hub 206 of tape reel 200 and/or a toothed hub 306of tape reel 300. The motor engages hubs 206 and 306 through clutches(not shown). When the clutches are disengaged from hubs 206 and 306, therotation of hubs 206 and 306 is prevented by a toothed circular brake207 and a toothed circular brake 307, respectively.

Squeeze bearing 4 assists in the control of vibration and entrained air.A squeeze bearing is a thin layer of a gas (such as air) used to supporta solid physical element. Here squeeze bearing 4 is an "implicit"squeeze bearing in that it is formed by allowing tape 1 to come withinclose proximity of itself--no ancillary devices are used. In actualoperation, squeeze bearing 4 does not allow tape 1 to contact itself. Atnormal operating velocities, a thin film of air is formed between thetwo surfaces of the tape. The two surfaces have identical velocities,thereby precluding wear of either surface. When tape 1 is motionless ormoving at low velocities (e.g. during start ups and stoppages), thesqueeze bearing collapses and the tape actually contacts itself. Ineither condition, the tape actually applies a force to itself. Theamount of force applied depends upon the winding rates, tensions, andgeometries. Squeeze bearing 4 damps tape tension variation, inhibitsvibration from tape reel 200 from being transmitted along the tape tothe head-tape interface at region 3, and exhausts entrained airotherwise entrapped between the wound wraps of the tape on tape reel300.

Still referring to FIG. 6, a tape head or pseudo-head, referencedgenerically by the letter X, is shown mated (i.e. in contact) with tape1 at head region 3. When tape cartridge 10 is inserted into a tape drive(not shown)and seated in the tape cartridge mount therein, as will bedescribed, X is a tape head. Bearings 105 and 125 guide tape 1 in theproximity of the tape head while minimizing friction and wear, as willalso be described. Such guiding permits the tape head to write data to,and read data from, tape 1. When tape cartridge 10 is not inserted intoa tape drive, access door 26 is closed and X is pseudo-head 29.

There is curvature (bowed into tape cartridge 10) in the path of tape 1between bearings 105 and 125, as shown in FIG. 6. Both the tape head andthe pseudo-head insert into the tape path of tape 1 to prevent it frombeing drawn taut straight between bears 105 and 125. Note that FIG. 6reveals the dimensions of tape 1. The dimension of tape 1 extending fromone tape reel to the other is referred to as the "length", the dimensionextending in and out of the figure is referred to as the "width", andthe remaining dimension is referred to as the "thickness".

Referring to FIGS. 7-8, a tape cartridge mount 400 of a tape drivesuitable for accessing data on tape cartridge 10 will be described.Mount 400 includes abase 401 having a tape head 402 mounted thereon.Head 402 may be any suitable for reading and writing data longitudinallyalong the length of a tape. For example, a thin film, interleaved,multi-track magnetic transducing head may be used. The individual datatracks may be accessed using inductive or magnetoresistive elements. Thedata may be recorded on the tape in any compatible format.

The seating of tape cartridge 10 in mount 400 permits the relativelateral positions of head 402 and the tape to be precisely controlled.Head 402 is wider than tape cartridge 10 and can be moved laterally (inthe direction perpendicular to the surface of base 401) relative to thetape to align the transducing elements of head 402 with the data trackson the tape. Head 402 is moved laterally by a stepper motor, voice coilmotor, or other known means. The head position relative to the tape maybe sensed by any known means, including a continuous servo loop. Furtherdescription of the head positioning means is not relevant to theinvention.

Base 401 has several cartridge registration stops mounted thereon todirect the tape cartridge (not shown) into the seated position as it isinserted in the direction represented by arrow 407. Two stops 403 and404 support the mass of the tape cartridge against the force of gravity.Another stop 405 prevents the tape cartridge from moving too far in thedirection of arrow 407. A door stop 409 maintains pivoting access door26 in the open position to expose the tape to head 402. Access door 26is first pivoted to the open position by a mechanism (not shown) in thetape drive. The tape cartridge is forced against two ball-headed stops410 and 411 at mounting portions 32 and 33, respectively, by theextension of a gas port 414. The rounded head of stops 410 and 411direct mounting portions 32 and 33 between the stops and base 401 as thetape cartridge is seated by movement in the direction of arrow 407. Twoclutch faces from the tape drive (remainder of the tape drive not shown)are not part of mount 400 and are shown positioned to permit simplemovement into engagement with toothed hubs 206 and 306 to firmly seatthe tape cartridge against a reference point 406.

Referring to FIGS. 9-11, tape cartridge 10 is shown seated in tapecartridge mount 400. Once again, tape 1 is not shown for convenience.Pivoting access door 26 is in the open position and tape head 402 isseated in head opening 27. The open position of access door 26 createsclearance for guide 410 to reach recess 30. Gas port 414 is in alignmentwith hole 61 in mount plate 12. A gas source 415 (shown only in FIG.8)in the tape drive may then provide gas into pneumatic tape guideassembly 100 to create a pneumatic gas bearing between the tape andbearings 105 and 125. Gas source 415 may be a suitable container ofcompressed gas, or may be a pump providing filtered ambient air to port414.

FIG. 9 shows clutch faces 416 and 418 disengaged from toothed hubs 206and 306, respectively. FIGS. 10-11 show clutch faces 416 and 418 engagedwith toothed hubs 206 and 306, respectively. Because tape cartridge 10is firmly positioned in the tape drive, pins 72 and 73 are also firmlypositioned. Hubs 206 and 306 thus have no radial play as they rotateabout pins 72 and 73. Universal self-axially-aligning clutches aretherefore used to ensure an accurate alignment of the axes of clutchfaces 416 and 418 to those of hubs 206 and 306. The firm seating of tapecartridge 10 in mount 400, combined with the precise alignment of tapereels 200 and 300 and bearings 105 and 125 to mount plate 12, result ina precise alignment of tape 1 to tape head 402 capable of the highestperformance.

Referring to FIGS. 12-13, pneumatic tape guide assembly 100 will now bedescribed. Assembly 100 includes aforementioned bearings 105 and 125,including plenums 110 and 130 and compliant members 120 and 140respectively. A gas entrance 150 is provided for mating with gas port414 through hole 61. Gas entrance 150 includes an interior Y-shaped pathto direct gas entering the tape cartridge through two tubes 124 and 144and into openings in plenums 110 and 130, respectively. Gas entrance 150also includes an opening 152 through which a screw 151 is inserted tothreadably attach assembly 100 to hole 59 of mount plate 12.

A first thin bearing foil 160 is secured to plenum 110 and a second thinbearing foil 180 is secured to plenum 130. Foils 160 and 180 includesmall perforations or holes therethrough (such holes are not shown inother figures for convenience). Foils 160 and 180 are secured to plenums110 and 130 by two solid, die-cut adhesives 161 and 181, respectively.Die-cut adhesive 161 has an opening 162 therein which matches an opening163 in plenum 110 to seal the gas path between plenum 110 and foil 160.Die-cut adhesive 181 has an opening 182 therein which matches an opening183 in plenum 130 to seal the gas path between plenum 130 and foil 180.Compressed gas entering into plenums 110 and 130 is thus forced throughsuch openings and exits out of the small holes in foils 160 and 180,respectively.

Compliant members 120 and 140 include guide elements for laterallyguiding the tape as it rides on the pneumatic, hydrostatic gas bearing.Foils 160 and 180 include recesses to permit the guide elements tolaterally position the tape, yet ensure that the tape is fully supportedacross its width throughout the remainder of the foils arc of curvature.

Full support is achieved by employing a tape which is wider than thefoils at the recesses, yet narrower than the foils away from therecesses. The width of the foils at the recesses is represented by anarrow 190; the width of the foils away from the recesses is representedby an arrow 191. Such full support allows for the use of very thin tape,yet prevents tape vibration disruptive to the head-tape interfacebecause the tape cannot fold over the edge of the bearing surface. Twoguide elements 121 and 122 fit within two recesses 126 and 127,respectively. Two guide elements 141 and 142 fit within two recesses 146and 147, respectively.

Referring to FIG. 14, a toothed hub tape reel of the tape cartridge willnow be described. Tape reel 200 is shown, but is also representative ofthe structure used in tape reel 300. Hub 206 is flanked by reel flanges209 and 210 and includes a set of circularly configured teeth 219 on arelatively small diameter portion 220. Circular brake 207 includes a setof circularly configured teeth 239, three long mounting pins 236-238,and three short mounting pins. Of the three short mounting pins, onlypins 231 and 232 are visible in FIG. 14. The long mounting pins andshort mounting pins are alternately spaced around the circularconfiguration of brake 207.

A circular well 215 in the top of hub 206 includes portion 220 and abase having six holes therein. The holes are spaced around the circularconfiguration of well 215. Of the six holes, only holes 211, 213 and 216are visible in FIG. 14. The three short mounting pins insert throughthree springs 221-223, respectively, and into three of the holes incircular well 215. For example, mounting pin 231 inserts into hole 211.The three long mounting pins 236-238 insert into three holes,respectively, in circular well 215. For example, mounting pin 236inserts into hole 216.

The aforementioned mounting of the pins results in hub 206 and brake 207being in a locked rotational relationship. Springs 221-223 bias brake207 toward cover 14. Normally, when tape cartridge 10 is removed from atape drive, the action of the teeth of brake 207 against a tab 214(shown in FIGS. 15 and 16) of cover 14 prevents rotation of reel 200. Inaddition, the contact between brake 207 and cover 14 prevent dust, wearparticles and other contaminants from entering the interior of tapecartridge 10.

To rotate reel 200 about axle 72, clutch face 416 (not shown in FIG. 14)is brought into engagement with the teeth of hub 206 and brake 207 todepress the teeth of brake 207 into well 215 against the bias of springs221-223. The clutch is then free to rotate reel 200 by rotatably drivinghub 206. When the clutch face is disengaged from reel 200, the biasingaction of springs 221-223 result in braking of the rotation of reel 200and seals the interior of tape cartridge 10 from contaminants bybringing brake 207 into contact with cover 14. Teeth 219 permit hub 206to be driven directly by clutch face 416, unlike the alternateembodiments described later herein. Such direct driving eliminates theadditional wear and tolerances associated with the driving arrangementsof the alternate embodiments.

Referring to FIGS. 15-16, the toothed hub tape reels will be describedas engaged with and disengaged from the clutch faces. Clutch face 416 isshown disengaged from hub 206; clutch face 418 is shown engaged with hub306. Such an orientation of the clutch faces is shown for theconvenience of illustration, in operation the clutch faces wouldgenerally engage and disengage simultaneously. Because only clutch face418 is shown engaged, pins 331 and 338 are shown resting deeper in theirrespective circular well holes than pins 231 and 238. Similarly, spring321 is compressed relative to spring 221. As a result, teeth 339 aredisengaged from a tab 314 of cover 14 and teeth 239 are engaged with atab 214 of cover 14.

Note that the lateral position of hub 206 between mount plate 12 andcover 14 is never altered because hub 206 is always biased against mountplate 12 by springs 221-223 or clutch face 416. Such a fixed positionallows for a permanent, precise registration of reel 200 to mountsurface 52 of mount plate 12 and the remainder of tape cartridge 10. Thefixed position also allows for a narrow, compact tape cartridge. Thetape can thus be guided at tolerances not previously achievable,resulting in improved tape path performance. When the fixed registrationof reel 200 to mount plate 12 is combined with the precise registrationof assembly 100 to mount surface 51 of mount plate 12 and the preciseregistration of tape head 402 to the tape, tape path performance isfurther enhanced.

Referring to FIG. 17, pivoting access door 26 will now be described. Asshown, upper flange 27 has been removed to reveal pseudo-head 29 and ananchor 75. Flanges 27 and 28 permit access door 26 to close the openingsin three walls of tape cartridge 10 which comprise head opening 25. Thethree openings are required to permit mating of tape head 402, which iswider than tape cartridge 10, to tape 1. The flanges also protectpseudo-head 29 from damage should access door 26 be opened when tapecartridge 10 is outside of a tape drive. Anchor 75 secures pseudo-head29 to the remaining body of access door 26 by interference fit. In thealternative, pseudo-head 29 may be secured to the remainder of accessdoor 26 with a suitable adhesive.

To insert tape cartridge 10 into the tape drive, access door 26 ispivoted to the open position and the cartridge is seated in mount 400with head 402 mated with the tape. Clutch faces 416 and 418 are thenbrought into engagement with hubs 206 and 306. To remove tape cartridge10 from the tape drive, clutch faces 416 and 418 are first disengagedfrom hubs 206 and 306 and the tape cartridge is withdrawn from mount400, allowing access door 26 to be pivoted to the closed position byspring 69. As previously described, the disengagement of the clutchfaces locks the rotational position of tape reels 200 and 300. Theclosing of access door 26 causes pseudo-head 29 to occupy the spacenormally occupied by the tape head when the tape cartridge is seated inmount 400. Such replacement eliminates slack in the tape otherwisepresent when the tape head separates from the tape, thereby maintainingconstant tape tension. Pseudo-head 29 may actually insert slightlyfurther into the tape path than tape head 402 to eliminate additionalslack resulting from the position of brake 207 at brake engagement. Inaddition, the presence of pseudo-head 29 prevents the tape from beingdrawn taut straight between bearings 105 and 125. Such a condition couldresult in stretching of the tape as the tape head is again mated withthe tape during re-insertion of tape cartridge 10 into the tape drive.

MANUFACTURE

The manufacture of tape cartridge 10 will now be described. Gas entrance150, tubes 124 and 144, and plenums 110 and 130 are molded from aplastic such as polycarbonate, which may be glass-filled to increase itshardness and/or rigidity. Adhesive sheets 161 and 181 are die-cut from asolid sheet of polyamide. Openings 162 and 182 are die-cut to have ashape which matches that of (but slightly larger than) openings 163 and183, respectively. Foils 160 and 180 are 2-4 mils thick polished brassor stainless steel foil which is lithographically etched to create theholes and edge recesses. Such materials and thickness are required tominimize cost while providing a foil of sufficient malleability that itcan be successfully and permanently bonded to the curved surfaces of theplenums. The underside of the foils are roughened by oxidation oretching with ferric chloride/nitric acid to improve bonding to theplenums. The foil is protected by coating with a solution of a silanecoupling agent (0.5%) or methanol in deionized water. The solution isapplied by dipping, spraying, or wiping. After curing, the foils arecoated with photoresist, patterned, and etched to create the airholesand recesses therein.

The plenums, adhesives, and foils are aligned in a fixture and heatedunder pressure to set the adhesive. Compliant members 120 and 140 areetched stainless steel. The gas entrance, tubes, plenums, foils andcompliant members are then assembled using the screws shown in thefigures and suitable adhesives to create the pneumatic tape guideassembly. The use of polished metal foils applied to a plastic plenumallows for a smooth, precisely shaped tape path at low cost.

Hubs 206 and 306, brakes 207 and 307, and the flanges of the tape reelsare molded plastic, such as polycarbonate, which may again beglass-filled. The flanges are attached to each hub using a suitableadhesive or ultrasonic welding and the brakes are mated therewith. Mountplate 12 is a piece of solid (i.e. not hollow) metal stock, such asstainless steel or anodized aluminum, which is machined to create thevarious surfaces thereon, including mount surfaces 51-53 in the sameplane. It is important that mount surfaces 51-53 be formedsimultaneously (in a single machining operation) to ensure that they areall in the same plane to within the tightest possible tolerance. Bothsides of mount plate 12 are machined to prevent warpage from residualstresses otherwise present after the machining of a single side. Solidmetal is used to ensure that mount plate 12 holds its dimensionaltolerances over time. After all of the holes are drilled in mount plate12, the mount plate is tumbled to round the hole and surface edges andthereby prevent tape edge damage from contact therewith.

The pivoting access door is manufactured from a molded plastic, such aspolycarbonate (which may again be glass-filled), with a flexible, lowdensity polyethylene pseudo-head. The flexibility of the pseudo-headallows for better control of tape tension. Because mount 400 is alignedto mount plate 10, the remaining parts of tape cartridge 10 (except forfoils 160 and 180) may be plastic, thereby achieving high performance atreduced cost. Tape 1 may be any known tape, such as magnetic or opticalaudio, video, or data storage tape. The active recording layer may beany known, such as chromium dioxide or metal particle magnetic layers.Tape 1 may be of any width, such as 1/4 inch, 1/2 inch or 8mm.

To assemble tape cartridge 10, tape 1 is wound entirely upon one tapereel. The pneumatic tape guide assembly, both tape reels, and pivotingaccess door are mated with the mount plate using the axles, pins andscrews shown in the figures and suitable adhesive, and tape 1 isthreaded through the tape portion to the other tape reel. Cover 14 isthen attached to the mount plate with screws to complete the tapecartridge 10. Base 401 and the reference stops of mount 400 aremanufactured from similar hard, durable materials such as brass,stainless steel, and polycarbonate.

ALTERNATE EMBODIMENTS

Referring to FIG. 18, an alternate embodiment of the tape cartridge isshown. Tape cartridge 10 is unchanged except that pneumatic tape guideassembly 100 is eliminated and replaced with two non-pneumatic tapeguides. Two plastic nearly D shaped bearings 510 and 530 replacebearings 105 and 125, respectively. Bearings 510 and 530 have solid tapebearing surfaces. Because a gas source is no longer used, gas entrance150, tubes 124 and 144, die-cut adhesive 161 and 181, and bearing foils160 and 180 are eliminated. To provide a smooth finish to the surfacesof bearing 510 and 530, such surfaces may be plated with thin layers ofmetal or covered with metal foils. Such metal foils are identical tofoils 160 and 180, except that the holes therein are eliminated, andthat adhesives 161 and 182 no longer need to be die-cut prior tobonding. In addition, hole 61 is eliminated from mount surface 51 andgas port 414 is eliminated from the accompanying tape cartridge mount.The the complaint guides are fitted within recesses molded into the edgeof bearings 510 and 530, and the edges of any plated metal or metalfoil.

Referring to FIGS. 19-23, another alternate embodiment of the tapecartridge is shown. Tape cartridge 10 is unchanged except that pivotingaccess door 26 is eliminated (as are its associated mounting hardware)and replaced with a sliding access door 626 having two flanges 627 and628. Access door 626 is slidably guided by a groove 668 and a similargroove on the reverse side of tape cartridge 19 (not shown). Access door626 is biased toward the closed position by a spring 669. The shape andlocation of the side recesses and mount portions are adjusted toaccommodate the change from pivoting access door 26 to sliding accessdoor 626. Thus, the two side recesses are now represented by numerals630 and 631, and the two mount portions are now represented by numerals632 and 633. A corresponding change is also required to the location ofthe cartridge guides on mount plate 401 (not shown).

Referring to FIG. 24, sliding access door 626 will now be described. Asshown, upper flange 627 has been removed to reveal pseudo-head 629.Access door 626 is slidably retained upon tape cartridge 10 by two tabs686 and 687 on flange 628, and similar tabs on flange 627, whichprotrude into and follow the aforementioned grooves. Access door 626 isshown in the closed position. In the open position, pseudo-head 629 ispressed flat against the base of access door 626 by the edge of thecover.

Referring to FIGS. 25-27, an alternate embodiment of the tape reels isshown. Tape reel 200 is unchanged except that brake 207 is eliminatedand replaced with a circular brake 707. Brake 707 includes teeth 739 anda vertically recessed circular drive ring 735. The clutch faces arealtered to mate with the new shape of the upper surfaces of the hub anddrive ring 735, but do not mate with teeth 739. In addition, tabs 214and 314 are eliminated and replaced with a tab which mates with teeth739, such as a tab 714. The teeth are eliminated from the relativelysmall diameter portion of the hub. The surface of drive ring 735 isroughened to provide enough friction between it and the clutch face toallow it to be driven thereby. If necessary, teeth may also be includedon drive ring 735 and the hub to provide for better mating.

Referring to FIGS. 28-30, another alternate embodiment of the tape reelsis shown. Tape reel 200 is unchanged from FIGS. 25-27 except that brake707 is eliminated and replaced with a circular brake 807. Brake 807includes a solid drive disk 835 (there is no opening in the center ofthe teeth) which may raise above the teeth. The height of the relativelysmall portion of the hub is reduced to allow clearance for disk 835.Disk 835 eliminates the seam that otherwise exists between therelatively small diameter portion of the hub and the drive ring, therebyimproving shielding against contaminants. Springs 221-223 are alsoeliminated and replaced with a finger spring washer 820 (shownexaggerated in FIGS. 29 and 30). Washer 820 includes three sets offinger springs 821-823. The three short mounting pins are thuseliminated from the brake, and three holes are eliminated from the hubwell.

While the invention has been described with respect to a preferredembodiment thereof, it will be understood by those skilled in the artthat various changes in detail may be made therein without departingfrom the spirit, scope, and teaching of the invention. For example, atape cartridge could be manufactured to include any combination of thealternate embodiments described. In addition, certain features describedherein could be embodied in a single reel tape cartridge (e.g. tape reel200)or in a tape drive (e.g. a tape guide with recesses 126 and 127).Accordingly, the invention disclosed herein is to be limited only asspecified in the follow claims.

What is claimed is:
 1. A tape cartridge comprising:a plate having a sidewith a first surface, a second surface, and a third surface thereon, thefirst surface, the second surface, and the third surface in a singleplane and separated from each other by at least one recess in the sideof the plate, the third surface including an edge and a portion interiorof the edge; a first tape reel on the first surface; a second tape reelon the second surface; a tape having a first end wound upon the firsttape reel and a second end wound upon the second tape reel; and a coveraffixed to the plate to form a box-like housing about the first tapereel and the second tape reel, the housing having an inside and anoutside, the majority of the side of the plate on the inside of thehousing, the cover having a plurality of walls adjacent the plate, oneof the walls having a recess therein exposing the portion of the thirdsurface interior of the edge to the outside of the housing.
 2. The tapecartridge of claim 1 wherein one of the walls has a plurality ofrecesses therein each exposing a portion of the third surface to theoutside of the housing.
 3. The tape cartridge of claim 1 wherein two ofthe walls each have a recess therein exposing a portion of the thirdsurface to the outside of the housing.
 4. The tape cartridge of claim 1further comprising a first tape guide affixed to the third surface onthe inside of the housing.
 5. The tape cartridge of claim 4 furthercomprising a second tape guide affixed to the third surface on theinside of the housing.
 6. The tape cartridge of claim 1 wherein theplate is anodized aluminum.
 7. The tape cartridge of claim 6 wherein thefirst surface, the second surface, and the third surface are formed in asingle plane by simultaneous machining.
 8. The tape cartridge of claim 1wherein the plate is stainless steel.
 9. The tape cartridge of claim 8wherein the first surface, the second surface, and the third surface areformed in a single plane by simultaneous machining.
 10. The tapecartridge of claim 1 wherein the first and second tape reels eachinclude a reel flange in said at least one recess, the reel flangehaving a tape edge guiding surface in the plane.
 11. The tape cartridgeof claim 10 wherein the third surface is a tape edge guiding surface.12. A tape cartridge comprising:a solid metal plate having aside with afirst surface, a second surface, and a third surface thereon, the firstsurface, the second surface, and the third surface formed in a singleplane and separated from each other by at least one recess in the sideof the plate, the third surface including an edge and a portion interiorof the edge; a first tape reel on the first surface; a second tape reelon the second surface; a tape having a first end would upon the firsttape reel and a second wound upon the second tape reel; a plurality oftape guides affixed to the third surface; and a cover affixed to theplate to form a box-like housing about the first tape reel, the secondtape reel, and the tape guides, the housing having an inside and anoutside, the majority of the side of the plate on the inside of thehousing, the cover having a plurality of walls adjacent the plate, oneof the walls having a recess therein exposing the portion of the thirdsurface interior of the edge to the outside of the housing.
 13. The tapecartridge of claim 12 wherein one of the walls has a plurality ofrecesses therein each exposing a portion of the third surface to theoutside of the housing.
 14. The tape cartridge of claim 12 wherein twoof the walls each have a recess therein exposing a portion of the thirdsurface to the outside of the housing.
 15. The tape cartridge of claim12 wherein the plate is stainless steel.
 16. The tape cartridge of claim12 wherein the plate is anodized aluminum.
 17. The tape cartridge ofclaim 12 wherein the first and second tape reels each include a reelflange in said at least one recess, the reel flange having a tape edgeguiding surface in the plane.
 18. The tape cartridge of claim 17 whereinthe first and second tape reels each include a reel flange in said atleast one recess, the reel flange having a tape edge guiding surface inthe plane.
 19. A tape drive and a tape cartridge suitable for use in thetape drive, the tape cartridge comprising:a plate having a side with afirst surface, a second surface, and a third surface thereon, the firstsurface, the second surface, and the third surface in a single plane andseparated from each other by at least one recess in the side of theplate, the third surface including an edge and a portion interior of theedge; a first tape reel on the first surface; a second tape reel on thesecond surface; a tape having a first end wound upon the first tape reeland a second end wound upon the second tape reel; and a cover attachedto the plate to form a box-like housing about the first tape reel andthe second tape reel, the housing having an inside and an outside, themajority of the side of the plate on the inside of the housing, thecover having a plurality of walls adjacent the plate, one of the wallshaving a recess therein exposing the portion of the third surfaceinterior of the edge to the outside of the housing; the tape drivecomprising: a mount suitable for seating the tape cartridge thereon, themount including a fourth surface; a tape head affixed to the mount; anda mount guide affixed to the mount such that a portion of the platerests between the mount guide and the fourth surface when the tapecartridge is seated in the mount, the mount guide inserted into therecess and against the third surface.
 20. The tape drive and tapecartridge of claim 19 further comprising an access door affixed betweenthe plate and the cover to pivot between an open position and a closedposition, the open position exposing the tape to the tape head andcreating clearance to the recess for the mount guide.
 21. The tape driveand tape cartridge of claim 19 wherein one of the walls has a pluralityof recesses therein each exposing a portion of the third surface to theoutside of the housing.
 22. The tape drive and tape cartridge of claim19 wherein two of the walls each have a recess therein exposing aportion of the third surface to the outside of the housing.
 23. The tapedrive and tape cartridge of claim 19 further comprising a plurality oftape guides affixed to the third surface on the inside of the housing.24. The tape drive and tape cartridge of claim 19 wherein the plate isanodized aluminum.
 25. The tape drive and tape cartridge of claim 24wherein the first surface, the second surface, and the third surface areformed in a single plane by simultaneous machining.
 26. The tape driveand tape cartridge of claim 19 wherein the plate is stainless steel. 27.The tape drive and tape cartridge of claim 26 wherein the first surface,the second surface, and the third surface are formed in a single planeby simultaneous machining.
 28. The tape cartridge of claim 19 whereinthe first and second tape reels each include a reel flange in said atleast one recess, the reel flange having a tape edge guiding surface inthe plane.
 29. The tape cartridge of claim 28 wherein the first andsecond tape reels each include a reel flange in said at least onerecess, the reel flange having a tape edge guiding surface in the plane.